An Heir To the Throne
by Randomness Girl
Summary: HeirTale AU (by Napstablook on Undertale Amino. I don't know what they're known as on other places.) What if it wasn't Asriel who brought Chara's body to the Surface? What if it was Toriel? How differently would the events before Frisk play out? ONE-SHOT


**A/N: I DID NOT COME UP WITH THIS AU! The AU, known as HeirTale, was created by Napstablook on Undertale Amino, through something they drew. I only got their permission to write this.**

 **Well, I suggest you get a few tissues, I honestly got myself to cry reading this, and I wrote it! That usually doesn't happen to me!**

 **Also, I'm not Toby Fox. Enjoy!**

* * *

"P-please..." Chara weakly spoke as they lay in bed, their eyelids barely open and their chest rising and falling erratically, "I... I want to s-see the flowers... Before I go..." They began to cough violently. Their pain could be seen though the way they scrunched up their face.

Asriel quickly grabbed the cup of water nearby, trying to get them to drink it. He knew, though, it was no use. Chara refused to consume anything but the buttercups. Everyone thought they felt too weak to eat, but in reality, it was part of the plan; the plan to free all the monsters.

Asriel silently wished it didn't have to go like this. _If only you can see how much this hurts Mom and Dad_ , he thought quietly. Tears streamed down the Queen's face as she loudly sobbed. The King, his father, placed a paw on her back, gently rubbing it to help comfort her. Asriel could tell, though, that he was worried as well, the way he stared at the dying human.

Chara had only been in their lives for a few years, yet they treated them as if they had always been a Dreemurr. It hadn't mattered that they were adopted, or human; they were family, and Asriel's best friend.

No longer able to view the sickening sight of death, Asriel crawled into his bed, trying to drown out everything. He shut his eyes, hoping, like he did every night, that this was only a dream.

* * *

Every morning, Asriel would wake up early, supposedly to check on Chara. Everyone knew the two were inseparable. In reality, it was to discuss the plan, and to continue to feed the buttercups to them. Asriel admired their bravery of sacrificing themselves for a race that wasn't their own, but he couldn't shake off the feeling of guilt that it was _him_ killing them.

He grabbed a few buttercups from the secret stash under his bed and reluctantly dragged his feet towards the other side of the room. He gave a weak smile. "Howdy, Chara," he whispered. "It's another beautiful morning."

No response.

"Chara?" He gave them a gentle shake on the shoulder. Nothing. He shook harder, tears sparkling at the corners of his eyes. "Chara?! Come on, this isn't funny! _Chara?!_ "

He remembered them telling him that when a human didn't seem healthy, you could check if they were okay by feeling how hot their forehead was. He gently lowered his free paw, the one with no flowers, under their bangs. Their skin was dead cold.

"Chara, NO!" the young prince screamed, dropping the flowers on the floor. The heavy footsteps of his parents were heard running outside the room. He quickly shoved the flowers under Chara's bed with his foot before they could notice as they rushed inside, still in their pajamas.

"What happened?"

"What is it, son?"

A giant lump formed in Asriel's throat, and he found it difficult to speak. He let the tears fall, no longer able to contain them.

His parents looked at the human child and gasped. Toriel quickly turned to Asgore, crying into his shoulder. He embraced her, letting a few tears crawl down his furry cheeks.

Asriel did his best to compose himself, rubbing his eyes to stop the tears. He could see their red SOUL leaving their body, as if it was begging him to absorb it. The plan had to be executed now.

"Mom, D-Dad," he began to announce, gaining their attention, "I'm going to take Chara's body back to the Surface."

His parents stared at him for a few silent moments. He took this as an okay from them. He began to lean over to Chara's bed to pick them up and absorb their SOUL, until his mother stopped him.

"Asriel, no," her firm but gentle voice commanded. Asriel froze in the position he was in and stared at her worriedly. He _had_ to convince her to let him go.

"B-but Mom!" he stuttered. "C-Chara sai- they asked to see them, the flowers! The one in the village!"

"Asriel, listen to your mother," Asgore told him firmly.

"B-but, but-"

Toriel sighed, her fur wet from crying. "Listen, Asriel," she said in a motherly tone. "Going to the Surface is dangerous, even if you do absorb their SOUL."

"I can do it! I'll be stronger with their SOUL!"

" _But you are merely a child!_ " she yelled a little harshly. Asriel flinched away from Chara.

"Look, son," his father said, hugging the young Boss Monster, "if Chara really wanted us to return them to the Surface, we can do it." He ruffled the tuft of fur on top of his little head. "You just stay here, where you can be safe."

Asriel remained quiet. He wanted to tell them why _HE_ had to take them, what they had planned, but he was sworn to secrecy. Even after their death, he wouldn't want to break their trust.

"I will take them to the Surface, Asriel," Toriel said, giving a small smile. "If it is what they truly wanted..."

"Tori, you do not have to do this," the King began, before he was interrupted.

"No, Gorey," Toriel stated. "It is no trouble at all. Besides, you still have a kingdom to watch over." She placed a paw on his cheek and placed her lips on his for a few seconds.

Normally, this display of affection would make Asriel want to gag, but he couldn't care less. There was no way to set the plan back to their original intentions.

"I will be fine, Asgore, do not worry." She softly caressed his beard, then proceeded to carefully pick up the human's body. A gust of air swirled gently around the female Boss Monster as she absorbed Chara's SOUL. As it died down, it was obvious she had gone through a transformation.

Her small horns had grown a tiny bit longer. Her fur was whiter than before. A black, zig-zagged line on each cheek went down from the bottom of her eye to her neck. Her robes hadn't changed much, but they gave off a slight glow, all the colors of a rainbow. Electricity appeared to softly surge through her paws.

"Stay safe, Tori," Asgore said softly, giving her an encouraging smile. He placed a firm paw on Asriel's shoulder.

The female Boss Monster have a gentle nod and walked out of the room. The other two followed her to the Barrier and watched as she passed right through, nothing holding her back.

Asriel gulped nervously. Would his mother learn of their plan? If so, would she even be willing to carry it out?

The father and son stood there a few more minutes before heading back into New Home for some breakfast.

* * *

The two sat by the fireplace in silence, waiting for hours for the Queen's return. However, hours turned into days, days turned into weeks, and weeks turned into months. No sign of her anywhere.

Many monsters, including Asriel, began to believe she was never coming back. Asgore, though, refused to accept that idea. Instead, he attempted to spread hope throughout the Underground, trying to keep the kingdom on the positive side, but bringing light to dark, gloomy subjects proved difficult and tiring.

A little bit over a year since Queen Toriel's disappearance, Dr. Gaster, the Royal Scientist, and Captain Gerson, head of the Royal Guard, arrived to New Home with unexpected news.

"Another human has fallen down, Your Highness!" Gerson announced as he and Dr. Gaster burst into the Throne Room.

The King and Prince looked up from their gardening. "Another?" Asgore repeated, sounding both hopeful and frightened.

Gerson opened his mouth to say something, but Dr. Gaster spoke before the Hammer of Justice could say anything. "Unfortunately, this one didn't survive the fall," he said, not much emotion in his voice. While he was usually a pleasant man, at his work, he was a different monster. As Asgore's ears drooped a bit, the Royal Scientist pulled out a jar-like container from his black coat. Inside, an orange heart floated, reminding Asriel of Chara's red SOUL.

"Luckily, we were able to contain its SOUL in here," he began to continue before being interrupted by King Asgore.

" _Their_ SOUL," the King corrected him. "The human is not an it."

"That hardly matters now, sir," Gaster snapped. Asriel hid behind his father's purple cape. Dr. Gaster usually frightened the young boy. "What matters is that we have a SOUL, so we might as well use it for something."

He studied the orange SOUL, contemplating what to do. "I can use it for my studies to-"

"No." Asgore looked at him and held out a paw. "Give them to me," he commanded gently. " _I_ will use the SOUL."

"Your Highness, what are you doing?" Gerson asked cautiously, adjusting the position of his hammer.

"I will use it to pass the Barrier and look for Toriel," the King declared, his eyes full of hope.

"Sir, that's a waste of this SOUL!" Gaster objected. "There is so much more we can use it for! Your search will be in vain, the Queen is long gone!"

"Toriel is out there somewhere, I know it!" Asgore responded. "I have to find her!"

"Asgore, you old _fool_!" Gaster sneered. Asriel gasped. Many monsters wouldn't dare to show such disrespect to the King. Asgore, however, ignored the scientist's rude remark. Instead, he asked once more for the SOUL.

"Captain, back me up," Gaster hissed to Gerson.

The turtle-like monster looked over at the King solemnly, then gave a gentle smile. "Your Highness," he said, "do whatever you feel is right."

Gaster's jaw dropped as he stared at the Captain of the Royal Guard in shock. Asgore took this opportunity to take the SOUL from his hands and absorb it. Just like with Toriel, a small gust of air swirled around the Boss Monster, bringing back memories to Asriel's mind.

Asgore's already large horns had become larger. His beard flowed with streaks of white and his hair grew in length, both shining as bright as gold. His cape waved in the wind, and the emblem of the Delta Rune glowed like the sun. Though he already had fire magic, small flames appeared to surround his paws.

Shielding his eyes from the Boss Monster's blinding light, Gerson said to him, "Good luck, Your Highness."

As the King marched towards the Barrier, he turned to the scientist and warrior. "Please," he told them, "watch Asriel while I am gone." And with that, he left the Underground.

* * *

Asriel's mind wandered as Gerson told another one of his stories. While they were fun to listen to, the young Prince couldn't help but fear for his father's safety. It had only been a few hours, but he was still worried to death. What if he ended up like his mother, missing forever and never to be found?

Gaster ran into the Family Room where the Prince and the warrior were spending time. The scientist was panting hard, sweat dotting his forehead.

Gerson raised an eyebrow. "Eh? What is it, Wingding?" he asked.

Dr. Gaster took a moment to catch his breath before replying, "Asgore... in... Throne... Room..." The two stood up worriedly as Asriel took a good look at Gaster's face. His cold, serious facade seemed to have dropped and was replaced with genuine fear. The captain and Prince ran after the scientist, silently hoping for the best.

In the Throne Room, next to the bed of golden flowers Asriel and Asgore had earlier tended to, knelt the King, many wounds on his fur. His body was no longer shining; instead, it was shaking like static, struggling not to become dust. The sight made Asriel want to throw up and cry.

"D-Dad," he stuttered softly, "are... what happened?"

Weakly, Asgore lifted his head, his sad eyes meeting his son's. "I... couldn't find her..." he choked out. Asriel felt tears rolling down his furry cheeks. "The humans... they... they saw me, and..." He closed his eyes slowly and gave a somber smile. "I'm sorry, Asriel..." he apologized softly. "I tried..."

And with those last words, the King let himself collapse. As his body hit the ground, it split into millions of pieces, covering the golden flowers in front of him. All that remained was a white SOUL, barely clinging to life.

"Dad!" the young prince cried. He hurried over to the SOUL and reached a paw out to grab it. Unfortunately, he was a split second too late; the SOUL shattered just before he could touch it.

Asriel stumbled a bit as he regained balance. He stared at his paw, too shocked to do anything.

His best friend had sacrificed themself in vain to save a race that wasn't theirs.

His mother had gone missing for so long.

Now, his father had just died in front of him.

 _And it was all his fault._

The remaining Dreemurr broke down, burying his face into his paws as he sobbed. _I never should've gone along with Chara's plan_ , he thought bitterly to himself.

* * *

Being the oldest (and now only) child of the King and Queen, Asriel quickly became the next ruler of the Underground. Already, much pressure was placed in the paws of the young teen.

Many were losing hope at the loss of their former monarchs. Others were doubting the abilities of the Prince-now-King to lead them. Indeed, he hardly had lessons from his parents in becoming a good ruler; the little knowledge he had came from watching his father and mother together as they made declarations, discussed future plans, and attended royal meetings. Luckily, he had Captain Gerson and Dr. Gaster to help guide him.

Clutching his father's ruby red trident tightly, King Asriel nervously marched into the meeting room where Dr. Gaster and Captain Gerson were waiting. The three of them were going to decide what the future course of actions would be: how to break the barrier and what to do with future fallen humans.

As he entered, the look on their faces told him that they already had an idea in mind.

"King Asriel," the scientist said, nodding respectfully. Asriel nodded back, his arms and legs numb with fright. "I'm sure you understand why we're meeting here?"

The young King sighed. "Of course, Dr. Gaster," he replied. "The barrier and humans."

Gaster smiled slightly, then continued. "Well, Gerson and I have been discussing this topic for a while, and we've come to an agreement that-"

"Wait, you've made plans without talking to me about them?" Asriel snapped. He could feel the fur on the back if his neck stand on edge with anger. Why didn't they let him include his input?

Dr. Gaster glared down at him with disgust. "Asriel," he stated, unwilling to address him properly, "this is something a mature adult needs to decide, _not_ a young boy."

"Just because I'm young doesn't mean I'm stupid!" the King retorted.

"Your Highness?" Gerson spoke up, placing a gentle hand on the young Boss Monster's shoulder. "Just... just hear us out, okay?"

Asriel took in a deep breath, then let it out. "Okay," he said, more calmly than before, "tell me what you've come up with."

What he heard only fueled his anger more.

"NO!" he yelled, stomping his foot and dropping his trident. "We are _NOT_ killing anyone!"

"King Asriel, there is no other way!" Gaster snapped hastily. "We need their SOULs to break the barrier, seven according to my research."

"But they don't deserve that!"

"Then what do you propose?!" Gaster yelled back. "Waiting for the next seven who fall to die a natural death?! Our people can't wait that long!"

Asriel huffed angrily, unable to come up with a response.

"Look, King Asriel," Gerson cut in as Gaster crossed his arms, "your subjects are mad at the humans for taking away your parents, and they're beginning to lose hope. You remember why hope is important, right?"

The young Dreemurr nodded and responded, "Hope is a key component to keeping a monster's SOUL alive."

Gerson nodded grimly. "Exactly. And, the Doctor and I have... come to an agreement that this... is the only way to give them that hope."

Asriel lowered his head. No, he refused believe that killing innocent humans was what he had to do! There had to be something else he could do! But, if it really was the only way to bring hope to the Underground, what else _could_ he do?

After what felt like an eternity, he let out a heavy sigh. "All right," he said, knowing he would regret those words in the future.

* * *

A long time had passed. How long? Asriel couldn't recall.

His people had rejoiced at the plan to take the humans' SOULs, and he was forced to slay his first one at the age of eighteen. Their pleas and cries still stung his heart, grief and guilt flooding his conscience.

The next five had fallen much sooner to his liking. Each time, he felt the same remorse he did as with the first one as they all unsuccessfully fought for their lives.

He pushed the thoughts out of his mind as he went to do what he did everyday: visit the human SOULs by the Barrier and talk. "Hey, guys," he told the colorful, floating hearts in the vessels. Of course, they remained silent. Not like they could respond to him.

He chuckled a bit, trying to cheer himself up. "Nice day today, huh? The birds are singing, the flowers are blooming, the usual." Still, nothing. "You guys doing fine?"

After a few moments, he sighed and rubbed the back of his neck. "Hey, I-I know I say this everyday, but... I'm sorry." He toyed with the trident in his paws before continuing. "It's just, they need the hope, y'know? A-and this... is the only way... and... I never wanted to do this to you guys, honestly." He gave a sad smile. "I know, you've heard this probably a billion times already."

A few awkward minutes of silence, then Asriel said, "Well, it was nice chatting with you guys." As he walked back into the Throne Room, he turned around and asked, "Same time tomorrow, okay?"

Entering the room, he walked passed the two thrones, both covered by a white sheet, and over to the bed of golden flowers, the same ones that his father had died on. "Hey, dad," he greeted them softly. Gardening was his father's favorite hobby, so he felt it right not to collect the dust and spread it somewhere else. "Another day, huh?" He took a deep breath, and began to tell the flowers something he had on his mind for a while. "I'm really trying to be a good king, but...

"I still don't believe this is the right thing to do. I know you would _never_ do something like this, and... you're probably very disappointed in me..." He let a single tear roll down. "I just... wish you were there to guide me... I don't have anyone anymore. Gerson retired a long time ago, and now Undyne is taking his place." He chuckled a bit. "Remember, the one I told you that I trained?

"Anyway, Gaster went missing, so he's replaced with Dr. Alphys. You don't know her, but she's a sweet gal, very passionate about her job. Heh, and a lot easier to talk to than Gaster."

A sigh. "Dad, everything is changing, and... I'm still here. I'm here just sitting around, killing innocent humans... I really wish you and Mom were here to help me and..."

Soft footsteps. The King turned around slowly and gasped. He had seen the sight too many times, but it never failed to catch him off guard.

A young human stood there, a worn dagger in their hand and a heart locket around their neck. Asriel felt himself choke up. "C-Chara?" he asked in disbelief.

The human child stared at him with confusion, tilting their head. Asriel laughed nervously, embarrassed. "Ah, I'm sorry," he apologized. "You just... remind me of someone else I once knew..." He gazed at them softly and began to frown.

"Even so, you know what I have to..." He trailed off, unable to finish. The human nodded grimly, tears sparkling in the corner of their small eyes.

"Just, go through once you're ready..." He solemnly walked out of the Throne Room and arrived at the Barrier.

Maybe it was a few seconds, maybe it was a few hours, he had no idea how long it was once the human arrived. Staring out where freedom lay, he told the human, "This is the Barrier. It's what keeps us all trapped down here."

He turned around to find the human practically crying. It stung at Asriel's own heart, his conscience screaming at him to stop this act.

 _No_ , he thought. _I must do this. For my people._

He pulled out his trident as the two entered a battle. Looking at the human, he felt worse. He could see that they hadn't hurt a single monster, yet here he was, punishing them for a crime they never committed; they didn't deserve this.

"Human, I..." He took one more look at them and saw...

A red SOUL.

 _Just like Chara's._

That was enough to shatter his already broken heart.

"I can't!" He fell to his knees, sobbing for the loss of his best friend all those years ago. "I'm sorry, human, but I can't go on like this! I can't let myself commit another senseless murder just for the freedom of my people..." He grit his teeth, unable to bear the emotional burden on his shoulders. "If Mom and Dad saw me, they..."

He sniffed as the human comforted him with a hug, crying with him.

He wrapped an arm around them in response. The two remained like that for who knows how long, before he stood up. "Human," he addressed them as he took his trident and aimed the prongs at his own chest. "Please, take my SOUL, leave this prison, and find another way to save my people. I..." He smiled somberly. "...I know you can."

He took a deep breath, adjusting his grip on his weapon.

 _Mom... Dad..._

 _Chara..._

 _See you soon..._

The last thing he heard were the human's cries, attempting to stop him.

* * *

 _ **THE END**_


End file.
